From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rock.gnat.com (rock.gnat.com [IPv6:2620:20:4000:0:a9e:1ff:fe9b:1d1]) by sourceware.org (Postfix) with ESMTPS id BBF3F3858D33; Fri, 17 Feb 2023 07:44:17 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org BBF3F3858D33 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 8B521116B6A; Fri, 17 Feb 2023 02:44:17 -0500 (EST) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id KQVK9y+aNuts; Fri, 17 Feb 2023 02:44:17 -0500 (EST) Received: from free.home (tron.gnat.com [IPv6:2620:20:4000:0:46a8:42ff:fe0e:e294]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rock.gnat.com (Postfix) with ESMTPS id 4E90D116B59; Fri, 17 Feb 2023 02:44:16 -0500 (EST) Received: from livre (livre.home [172.31.160.2]) by free.home (8.15.2/8.15.2) with ESMTPS id 31H7iBDi092654 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 17 Feb 2023 04:44:11 -0300 From: Alexandre Oliva To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org Subject: [PATCH] [libstdc++] ensure mutex_pool survives _Safe_sequence_base Organization: Free thinker, does not speak for AdaCore Errors-To: aoliva@lxoliva.fsfla.org Date: Fri, 17 Feb 2023 04:44:11 -0300 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 X-Spam-Status: No, score=-12.3 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_STATUS,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On vxworks, after destroying the semaphore used to implement a mutex, __gthread_mutex_lock fails and __gnu_cxx::__mutex::lock calls __throw_concurrence_lock_error. Nothing ensures the mutex_pool mutexes survive init-once objects containing _Safe_sequence_base. If such an object completes construction before mutex_pool initialization, it will be registered for atexit destruction after the mutex_pool mutexes, so the _M_detach_all() call in the _Safe_sequence_base dtor will use already-destructed mutexes, and basic_string/requirements/citerators_cc fails calling terminate. This patch fixes this problem by ensuring the mutex pool completes construction before any _Safe_sequence_base-containing object, so that the mutex pool survives them all. Regstrapped on x86_64-linux-gnu. Tested on arm-vxworks7 (gcc-12) and arm-eabi (trunk). Ok to install? for libstdc++-v3/ChangeLog * include/debug/safe_base.h (_Safe_sequence_base): Ensure the mutex pool survives *this. --- libstdc++-v3/include/debug/safe_base.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/include/debug/safe_base.h b/libstdc++-v3/include/debug/safe_base.h index 1dfa9f68b65b5..d4ba404cdac6e 100644 --- a/libstdc++-v3/include/debug/safe_base.h +++ b/libstdc++-v3/include/debug/safe_base.h @@ -203,7 +203,15 @@ namespace __gnu_debug // Initialize with a version number of 1 and no iterators _Safe_sequence_base() _GLIBCXX_NOEXCEPT : _M_iterators(0), _M_const_iterators(0), _M_version(1) - { } + { + // Make sure the mutex_pool machinery is initialized before any + // full object containing a _Safe_sequence_base completes + // construction, so that any local static mutexes in the mutex + // pool won't be destructed before our destructor runs; + // _M_detach_all could fail otherwise, on targets whose mutexes + // stop working after being destroyed. + (void)this->_M_get_mutex(); + } #if __cplusplus >= 201103L _Safe_sequence_base(const _Safe_sequence_base&) noexcept -- Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer Disinformation flourishes because many people care deeply about injustice but very few check the facts. Ask me about